1. Field of the Invention
This invention relates to cameras and more particularly to a magnification variable camera which has a photographed picture size switching mechanism so that the size of the photographed picture may be variable.
2. Related Art Statement
Recently the functions of cameras are multiple and switching a photographed picture size is one of them. Such switching of a photographed picture size relates to switching, for example, a normal size to a half size or to a panorama size. In such camera, the visual field of the finder must be switched as operatively connected with the switching of the photographed picture size. Numerous suggestions have been made on these switching mechanisms.
The disclosure in the publication, for example, of Japanese patent application laid open No. 207731/1989 relates to a technique of a zooming driving system of a photographing lens and a zooming driving system of a finder operatively connected with it. According to these systems, it is possible to operatively connect a finder visual field frame with the switching of the above mentioned photographed picture size by adding a photographed picture size switching mechanism.
However, in the disclosure in this publication, only the finder visual field frame is merely driven as operatively connected with the switching of the photographed picture size and the picture of the finder becomes so small as not to be desirable in use. FIG. 43 shows a finder visual field frame Fn at the time of the normal photographing with the camera, that is, at the time of photographing a normal size picture. FIG. 44 shows a finder visual field frame Fp1 showing that, when a photographed picture size is switched to a half size use, the finder visual field frame will be also switched as operatively connected. This visual field frame Fp1 is of a picture in which the finder magnification is not varied but is merely made narrow and therefore has a disadvantage that the observation with it is difficult.
The disclosure in the publication of another Japanese patent application laid open No. 107240/1989 relates to a means for switching a finder visual field and finder magnification at the time of trimming, that is, at the time of switching a photographed picture size. However, the means for switching the finder magnification is to switch the magnification of the finder eyepiece.
However, in the disclosure in this publication, when the photographed picture size is switched, simultaneously with switching the finder visual field, the magnification of the finder eyepiece will be made large. However, in order to enlarge the magnification of the finder eyepiece, the structure of the eyepiece will inevitably become complicated and large. Usually, such eyepiece is arranged in the upper part of the back surface of the camera. If this part becomes large, it will be disadvantageous in utilizing and carrying the camera. If the finder magnification is made extremely large, the strain and dust on the image forming surface of the finder will be observed as magnified, the precision in making the finder will have to be further improved. the dust will have to be more carefully prevented in assembling and therefore the problem of the high cost will be produced.
The photographing area converting apparatus in a camera disclosed in the publication of Japanese utility model application publication No. 25058/1960 relates to a full size and half size photographed picture switching mechanism switching by operatively connecting a real picture mask and finder mask by a manual operation.
In the apparatus disclosed in this publication, the size is switched by a manual operation and therefore can not be switched by one touch by the user and, in case the required operation amount of the operating member is large, a large operating member space will have to be provided in the outer appearance part of the camera body and there will be such disadvantage that a restriction will be produced to the design. Further, in the apparatus disclosed in the publication, when the picture size is switched from the full size to a half size, the finder visual field will be covered on both sides so as to be for a half size. In such case, the finder visual field will be so small as to be disadvantageous to finder observation.
In the camera aiming at a pseudo telescopic effect disclosed in U.S. Pat. No. 743,470, when the telescopy with the full size is exceeded, the real picture will be switched to a trimming mode and, at the same time, the finder will be elevated in the magnification with the visual field frame constant as it is to set it on the narrow telescopy side. However, in the disclosure in this publication, the zooming region of the finder system can be set as expanded to be larger than the zooming region of the photographing optical system and its effect can be developed only in the trimming region exceeding the telescopy limit of the photographing optical system. Therefore, there is no effect on setting the picture size within the zooming region of the photographing optical system.